1. Field of the Invention
The present invention relates to an integrated optical component and its manufacture. More specifically, it concerns a process for making an integrated optical component containing optical fiber positioning grooves in alignment with waveguides formed in the component.
One of the difficulties encountered in the industrial production of integrated optical components, such as connectors, couplers and the like is to obtain a precise positioning of the optical fibers in relation to the waveguides or optical circuit channels arranged in the component, the positioning of the fiber in front of the end of the optical circuit to be insured within a precision of one micrometer or even less.
2. The Prior Art
Integrated optical components have been produced using ion diffusion techniques. U.S. Pat. No. 4,765,702 depicts an integrated optical component having a monolithic glass body with at least one optical circuit path formed through ion exchange on its surface. The optical circuit path has the same constituents as the glass body plus ions which increase its refractive index to a value greater than that of the glass body. The glass body is provided with, on at least one of its sides where the optical circuit path exits, a sectioned cavity molded into the glass body. The optical circuit path ends at the sectioned cavity and is aligned with it in such a way that an optical device, for example, an optical fiber, is positioned in the cavity and thereby optically aligned with the optical circuit path. The sectioned cavity can be formed with a transverse section groove in the shape of a V. This integrated optical component can be manufactured by a process consisting of:
(a) molding with high precision a monolithic glass body having a sectioned cavity on at least one of its sides, and
(b) forming in the piece obtained in (a), at least one optical circuit path by the ion exchange, i.e., ion diffusion, technique, with one end of this path being aligned with the sectioned cavity in such a way that an optical device positioned in the the cavity is optically aligned with the optical circuit path.
This integrated optical component can be, for example, a connector, a coupler-divider, a single-mode coupler, a single-mode multiplexer coupler, a multimode multiplexer coupler, a coupler allowing an optical fiber to be lined up with a collimating lens, or a multimode monitor.
However, in the component described in U.S. Pat. No. 4,765,702, the alignment precision of the sectioned cavities with the optical circuit paths is very delicate, especially for the manufacture of single-mode couplers which require a greater precision in positioning the fibers than the multimode couplers.
U.S. patent application Ser. No. 166,388 filed Mar. 10, 1988 teaches an integrated optical component comprising a glass substrate with at least one ion diffused optical circuit path connected to at least one optical fiber. The component further comprises at least one transverse exit groove forming a vertical lateral surface at a termination of the optical circuit path, an endface of the optical fiber abutting the termination at the vertical lateral surface; plateau support means adjacent the side of the transverse exit groove opposite the optical circuit path for supporting an uncoated portion of the optical fiber; second support means adjacent the side of the plateau support means opposite the optical circuit path for supporting a coated or sheathed portion of the optical fiber; and, first adhesive means for securing the optical fiber endface to the vertical lateral surface. This integrated optical component can be manufactured by a process consisting of: (a) forming a glass body substantially in the form of a rectangular glass block; (b) creating at least one optical circuit path in the glass body by ion exchange; (c) mechanically machining at least one transverse exit groove to create a termination for the optical circuit path; (d) mechanically machining a transverse support shoulder for supporting a coated or sheathed portion of the fiber; (e) forming plateau support means for supporting an uncoated portion of the fiber; (f) approximately aligning an endface of the fiber with the optical circuit path termination; (g) precisely aligning the fiber endface and the optical circuit path termination by means of a micromanipulator tool; and (h) securing the fiber endface to the optical circuit path termination with an adhesive means.
Because of the manner in which the glass block is formed in the method of U.S. patent application Ser. No. 166,388, the fiber endface must initially be approximately aligned and thereafter precisely aligned by means of a micromanipulator tool.
It is therefore an object of the present invention to provide a method of making an integrated optical component to which optical fibers can be easily and precisely aligned.